United States Environmental Protection Agency, Region 9 

Air Division 

Technical Support Document 

for 

EPA’s Notice of Proposed Rulemaking 

for the 

California State Implementation Plan 

San Joaquin Valley Unified Air Pollution Control District’s 

Rule 4308, Boilers, Steam Generators and Process Heaters – 0.75 to less than 2.0 MMbtu/hr 

Prepared by: Idalia Pérez 

July 2010 
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San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) 

Submitted Rule 

SJVUAPCD Rule 4308, Boilers, Steam Generators and Process Heaters – 0.75 to less than 2.0 

MMbtu/hr 

 Adopted: December 17, 2009 

 Submitted: May 17, 2010 

 Determined complete: June 8, 2010 

Previous Rule Submittals 

There are no outstanding submittals of Rule 4308. 

SIP-Approved Rule 

 Adopted: October 20, 2005 

 Approved by EPA: May 30, 2007 (72 FR 29886) 

Rule Summaries 

Rule 4308 limits NOx and CO emissions from boilers, steam generators, process heaters and 

water heaters with a total rated heat input equal or larger than 0.075 MMBtu/hour and less than 2 

MMBtu/hour. 

Rule Amendments 

Rule 4308 was amended to include specific limits for instantaneous and pool water heaters as 

well as to strengthen the NOx emission limits for other units. 

Section 4 (Exemptions) was changed to add an exemption for units in recreational vehicles. 

Section 5.3 was changed to include new NOx limits. 

Other changes were done to improve consistency, clarity and enforceability of the Rule. 

Effects on Emissions 

The District estimates that the total baseline emission inventory for this source category is 3.39 

tons of NOx per day (tpd). The District expects a total emission reduction of 2.77 tpd to be 

achieved by 2031, assuming all units will be replaced over a 20 year period based on the useful 

life of a typical unit. 

Rule Evaluation 

Generally, SIP rules must be enforceable (see §110(a) of the Clean Air Act, hereafter CAA); 

must require Reasonably Available Control Technology (RACT) for major sources of NOx in 

nonattainment areas (see CAA §182(b)(2) and (f)); must not interfere with applicable 

requirements, including requirements concerning attainment (see CAA §110(l)); and must not 

relax existing requirements in effect prior to enactment of the 1990 CAA amendments (see 

§193). In addition, SIP rules must implement Reasonably Available Control Measures (RACM) 

for PM2.5 nonattainment areas (see CAA section 172(c)(1)). 
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SJVUAPCD regulates an extreme nonattainment area for the 1-hour ozone standard, a severe 

nonattainment area for the 8-hour ozone standard (40 CFR 81), and a PM2.5 nonattainment area, 

thus, submitted Rule 4308 must fulfill RACT and RACM requirements. 

Guidance and policy documents that we used to define specific enforceability, RACT and 

RACM requirements include the following: 

• Issues Relating to VOC Regulation, Cutpoints, Deficiencies, and Deviations (the "Blue 

Book"), US EPA, OAQPS (May 25, 1988). 

• Guidance Document for Correcting Common VOC and Other Rule Deficiencies, EPA 

Region IX (August 21, 2001, the “Little Bluebook”).

• State Implementation Plans; General Preamble for the Implementation of Title I of the 

Clean Air Act Amendments of 1990, 57 FR 13498 (April 16, 1992); 57 FR 18070 (April 

28, 1992). 

• Determination of Reasonably Available Control Technology and Best Available Retrofit 

Control Technology for Industrial, Institutional, and Commercial Boilers, Steam 

Generators, and Process Heaters, CARB (July 18, 1991). 

http://www.arb.ca.gov/ractbarc/boilers.pdf

• Alternative Control Techniques Document-- NOx Emissions from 

Industrial/Commercial/Institutional (ICI) Boilers, US EPA 453/R-94-022 (March 1994). 

http://nepis.epa.gov/EPA/html/Pubs/pubtitleOAR.htm

• Alternative Control Techniques Document-- NOx Emissions from Utility Boilers, US 

EPA 452/R-93-008 (March 1994). http://nepis.epa.gov/EPA/html/Pubs/pubtitleOAR.htm

RACT and RACM

SJVUAPCD included a RACT analysis in the Rule’s Staff Report (pages 13 – 15). In summary, 

SJVUAPCD found that: 

- This source category is not subject to national requirements (NSPS, NESHAP, 

MACT); 

- Rule 4308 has comparable emission limits to SCAQMD Rule 1146.2 and BAAQMD 

Rule 9-6. 

We concur with SJVUAPCD’s conclusion that Rule 4308 implements RACT for NOx emissions 

for reasons including: 

- SJVUACPD’s Rule 4308 is as or more stringent than SCAQMD, SMAQMD and the 

other large California nonattainment agencies. These Districts generally have among 

the most stringent stationary source requirements nationwide, and we are not aware of 

other reasonably available technological or operational controls likely to significantly 

reduce additional emissions from this activity. 

- Both 1994 ACT documents mentioned above provide technical information including 

control techniques and achievable controlled NOx emission levels from boilers. Rule 

4308 requirements are as or more stringent than the ACT. 

- The submitted rule is as stringent as CARB’s RACT/BARCT guidance. 
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Since no CTG has been issued recently for this activity, we do not have clear national guidance 

defining presumptive RACT. However, we believe the analysis summarized above sufficiently 

demonstrates that Rule 4308 implements RACT. 

We are aware of no guidance or other basis to conclude that PM2.5 RACM requirements 

necessitate more stringent controls for these sources than do ozone RACT requirements. 

Therefore, we believe that the demonstration of ozone RACT summarized above also 

demonstrates implementation of PM2.5 RACM. 

Enforceability 

Recordkeeping and other compliance provisions in the rule ensure that the requirements are 

adequately enforceable. 

CAA §110(l) and §193 

SIP rules must not interfere with applicable requirements, including requirements concerning 

attainment (see CAA §110(l)) and must not relax existing requirements in effect prior to 

enactment of the 1990 CAA amendments (see §193). 

SJVUAPCD added a new exemption for units in recreation vehicles (RVs) to Rule 4308 for 

consistency with other Districts’ rules for this source category, mainly SCAQMD Rule 1146.2 

which was approved into the SIP on 12/05/08 (73 FR 74027) and has this exemption. The Staff 

Report indicates that there are very few units in RVs that would be subject to this rule due to 

size. According to the District, most units in recreational vehicles are 12 gallons in size while a 

typical 75,000 Btu unit is 80 gallons in size. SJVUAPCD also notes that it would be difficult to 

enforce requirements for RVs as the units are in mobile units and these could come from outside 

of the District jurisdiction. The District further notes that these units are not used frequently thus 

they do not contribute a significant amount of NOx to the inventory. Because of this, we believe 

that the added exemption does not interfere with attainment. In addition to this, the inclusion of 

more stringent NOx emission limits make the amendments a strengthening of the SIP and 

complies with CAA §110(l) and §193. 

Suggested Rule Improvement 

EPA recommends that the SJVUAPCD make the following improvement in the next revision of 

Rule 4308: 

1. The exemption for units in recreational vehicles (§ 4.2) should be eliminated. 

2. The emission limits for instantaneous and pool water heaters between 0.075 and 0.4 

MMBtu/hour should be as stringent as for other units of this size. 

3. The Rule should specify that liquid fuel must be low in sulfur to further reduce PM2.5 

precursor emissions. 

Recommendation 

EPA staff recommends approval of SJVUAPCD submitted rule 4308 for incorporation into the 

California Applicable SIP. 

Attachments 

1. Submitted Rule 4308 (Clean Copy) 
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2. Submitted Rule 4308 (Strikeout Copy) 

3. Staff Report 

4. SIP-approved version of Rule 4308